A technique that can extend an I/O fabric, of a computer, which is realized using printed wiring on a board (e.g. a mother board) mounted with a CPU (Central Processing Unit), a memory, an I/O (Input/Output) bus, and the like configuring the computer, to the outside of a housing of the computer by use of a network cable and a network switch is emerging.
An I/O device enclosure box for mounting a GPU (Graphics Processing Unit) connected to PCI (Peripheral Component Interconnect)-Express (PCI-Express is a registered trademark of PCI-SIG) and an I/O device such as an NIC (Network Interface Card) and the like is known (e.g. the Internet URL: http://www.magma.com/). In the I/O device enclosure box, an I/O fabric of PCI-Express is extended from a computer to the outside of the chassis by use of a dedicated I/O card and a cable, and the cable and the I/O device enclosure box are connected. By this, the I/O device disposed at a point physically distant from the housing of the computer can be used from the computer. In this product, a signal flowing through the cable conforms to specifications of PCI-Express. Further, a distance between the housing of the computer and the I/O device enclosure box is several meters. Therefore, the extent of connection in a server rack (e.g. a 19-inch rack of EIA (Electronic Industries Alliance) Standards: width per stage: 19 inches, height is specified by multiples of 1.75 inches. A unit of 1U is defined by 1.75 inches.) is a reachable distance.
Further, a product (e.g. ExpEther), which uses Ethernet (registered trademark) for connection between a computer and an I/O device enclosure box, is known (e.g. the Internet URL: http://www.nec.co.jp/products/workstation/solution/expether/). In this product, a signal of PCI-Express (registered trademark) is encapsulated by an Ethernet (registered trademark) packet, and thereby it is possible to extend a physical distance between a housing of a computer and an I/O device enclosure box to a distance (up to kilometer units) specified by specifications of Ethernet (registered trademark) using an Ethernet (registered trademark) cable and an Ethernet (registered trademark) switch.
In the above-described product or the like, the Ethernet (registered trademark) switch is used for connecting mainly the I/O device enclosure box and the computer. To be more accurate, the switch is used for connecting a root complex and an endpoint (in PCI-Express (registered trademark), an I/O device is referred to as an “endpoint”) in a PCI-Express (registered trademark) fabric.
On the other hand, computers can also be connected by use of a non transparent bridge (NTB). The NTB connects root complexes in a PCI-Express (registered trademark) fabric directly or via a PCI-Express (registered trademark) switch and a PCI-Express (registered trademark) bridge. The root complex is a device located in a root (the root of a hierarchy) of a PCI-Express (registered trademark) fabric within a computer. The root complex includes a PCI-Express (registered trademark) port and a host bridge and provides an interface for accessing an I/O device within the PCI-Express (registered trademark) fabric from a CPU.
The NTB appears as an endpoint from each CPU (or root complex). The NTB provides an interface used in data forwarding and the like for each CPU. The NTB executes, via the interface, processing for converting information indicating a transmission destination of data being transmitted from one CPU, and for transmitting the data to the other CPU.
When the above-described related techniques are used, it is possible to divide a server placed in a datacenter into resource units such as a CPU, a memory, an I/O device, and the like, and realize a resource-separated datacenter in which the resource units are flexibly connected via a network (see, for example, NPL 1).
In a product (e.g. ExpEther) using Ethernet (registered trademark) for connecting a computer and an I/O device enclosure box, the I/O device enclosure box and the computer are configured to include I/O interfaces corresponding to the product, respectively. Each I/O interface is assigned with a MAC (Media Access Control) address. When the I/O device arranged in the I/O device enclosure box or the computer transmits a signal of PCI-Express (registered trademark), the I/O interface encapsulates the signal of PCI-Express (registered trademark) using an Ethernet (registered trademark) packet. At that time, a MAC address of an I/O interface included in an I/O device enclosure box or a computer to be a transmission destination of the signal of PCI-Express (registered trademark) is set for a destination MAC address included in the Ethernet (registered trademark) packet, and the MAC address of the own I/O interface is set for the transmission source MAC address.
The encapsulated signal of PCI-Express (registered trademark) flows on Ethernet (registered trademark) on the basis of the MAC address and is delivered to the I/O interface indicated by the destination MAC address.
In the destination I/O interface, the signal of PCI-Express (registered trademark) is extracted (decapsulated) from the Ethernet (registered trademark) packet, and the signal of PCI-Express (registered trademark) is finally delivered to the I/O device or the computer.
In the product in which Ethernet (registered trademark) is used for connecting a computer and an I/O device enclosure box, connection between the I/O device enclosure box and the computer is controlled by use of a VLAN (Virtual Local Area Network). An I/O device enclosure box having a VLAN ID matched with that of a computer is treated as an I/O device enclosure box capable of using the computer.
PTL 1 discloses a configuration for solving a problem that to construct a large number of VLANs on a network, a cost increases according to addition of network devices and the like. PTL 1 discloses a switching apparatus including a plurality of ports, the apparatus including a switch information storage unit that stores an output port identifier for a combination of an input port identifier, an input virtual path identifier, and a transmission destination address; a detection unit that detects a first input virtual path identifier and a first transmission destination address provided for an input packet; a retrieval unit that retrieves a first output port identifier from the switch information storage unit on the basis of a first input port identifier for identifying a port to which the input packet is input, the first input virtual path identifier, and the first transmission destination address; and a packet switch unit that forwards the input packet to a port identified by the first output port identifier.
PTL 2 discloses a switch node in which a plurality of CPUs and a plurality of extended NW IFs are connected using a multi-root compatible PCI-Express (PCIe) switch, a switch port based on a plurality of extended network interfaces (NW IFs) is configured, and a large-capacity flow table is configured using a software-based switch node.